Methods of Waterproofing

Among those sold in powder form are the following: Hydrated Lime ("Crown Hydrate," "Tiger Brand White Rock Finish," etc.); "Ideal" Waterproofing Filler; " Trus-Con" Waterproofing Filler; "Anhydra;" "Hydra tite ;". Hydrolithic Cement; "Medusa" Water Proof Compound; " Whitehall" Waterproofing Compound; "Toxement," etc.

Among those which come in the form of a solution are : " Anti-Hydro ;" "Aquabar," etc.

Anhydra.

This is a white, dry powder re sembling talcum powder in appearance and texture. Like all other waterproofing com pounds, it must be very thoroughly mixed with the other ingredients in the concrete to get the best results. When added to cement in the pro portion of two per cent of the weight of the neat cement, it is claimed to render any con crete in which this cement is used in reasonable proportions permanently impervious to water, and to do so without stain or discoloration. Its proprietors proclaim for it a very wide range of adaptability—for the top dressing of floors; for the waterproofing of cellars and basements, swimming pools, tanks, silos and reservoirs, concrete blocks, etc.

This proprietary compound for waterproofing purposes is described by the manufacturers as "a solution, neutral to cement, which, when added in certain percentage to the water used in mixing Portland cement in the usual way, has the effect, without retarding its setting, of rendering the cement in all kinds of masonry impervious to water, moisture, frost, gas, odors, etc. It hardens and increases the tensile strength fully 25 per cent, makes more uniform and composite the texture, and over comes in a large measure the non-resilience of the cement mixtures to strains and shocks. It makes them dustless and gives no discoloration. It acts upon cement while it sets; increases the natural density of that material, and in so doing draws together all the other constituents of a concrete, mortar, or stucco, intensifying the congestion so that their hygrometric natures are changed, and capillary action and percolation prevented." Cement coatings treated with this compound are said to be "fireproof, besides being non-Conductors. In color they are light gray, but can be given almost any color. The bond to brick, stone, concrete, or to cement finished surfaces is perfect, adhering permanently against any head of water." The compound is also claimed to establish in concrete a resistance to acid conditions.

In the waterproofing of walls, floors, etc., under moderate conditions of wetness, the best results with this compound are said to be at tained by using a stucco or mortar about three quarters of an inch thick, applied in the follow ing manner: The surface must first be absolutely cleaned of all paint, whitewash, or other foreign sub stances, and must be "roughed" sufficiently for the cement to bond to, and be well dampened.

Next, a "slush coat" or grout of neat cement, mixed with water in the proportion of one part of the compound to ten parts water, is applied.

This is followed with a "scratch coat" one fourth • to three-eighths inch thick, one part cement to two parts clean, sharp sand, mixed with water containing the same proportion of the compound as for the slush coat.

Finally, after the scratch coat has had its initial setting, a "finish coat" one-fourth to three-eighths inch thick is applied, mixed, one part cement to one part clean, sharp sand, with water containing the same proportion of the compound as for the previous coats, one to ten. The finish coat should be well troweled.

Aquabar.

The waterproofing compound sold under this name is a paste-like solution, which is used by being diluted in the water with which the cement is tempered. The proportions rec ommended are one part of the compound to twenty-four parts of water. It is claimed to be efficient in establishing water-tightness even against heavy pressure, and to be of such com position that it will not evaporate from mortar or concrete or lose its obstructive qualities with age. Its action is described as "that of filling all the voids or pores to such an extent as to make the cement mortar, when set, entirely moisture-proof." It may be used in the lightest kind of block work or the heaviest form of mass work, in joints, in facing for concrete work, or may be applied merely as a surface coating to concrete, stone, brick, terra-cotta, etc. On ac count of the simplicity of mixing, it may be handled by unskilled labor and manipulated with perfect freedom and deliberation. It is claimed not to discolor or stain, and not to affect in any material degree the strength of concrete in which it is used. Also, it is said to contain no constituents tending to corrode steel, so that it may safely be used with concrete in which expanded metal, metal lath, wire fabric, steel rods, shapes, etc., are embedded.